Prevalence and impact of unknown diabetes in the ICU

David L. Carpenter, Sara R. Gregg, Kejun Xu, Timothy G. Buchman, Craig M. Coopersmith*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

47 Scopus citations


Objectives: Many patients with diabetes and their care providers are unaware of the presence of the disease. Dysglycemia encompassing hyperglycemia, hypoglycemia, and glucose variability is common in the ICU in patients with and without diabetes. The purpose of this study was to determine the impact of unknown diabetes on glycemic control in the ICU. Design: Prospective observational study. Setting: Nine ICUs in an academic, tertiary hospital and a hybrid academic/community hospital. Patients: Hemoglobin A1c levels were ordered at all ICU admissions from March 1, 2011 to September 30, 2013. Electronic medical records were examined for a history of antihyperglycemic medications or International Classification of Diseases, 9th Edition diagnosis of diabetes. Patients were categorized as having unknown diabetes (hemoglobin A1c > 6.5%, without history of diabetes), no diabetes (hemoglobin A1c < 6.5%, without history of diabetes), controlled known diabetes (hemoglobin A1c < 6.5%, with documented history of diabetes), and uncontrolled known diabetes (hemoglobin A1c > 6.5%, with documented history of diabetes). Interventions: None. Measurements and Main Results: A total of 15,737 patients had an hemoglobin A1c and medical record evaluable for the history of diabetes, and 5,635 patients had diabetes diagnosed by either medical history or an elevated hemoglobin A1c in the ICU. Of these, 1,460 patients had unknown diabetes, accounting for 26.0% of all patients with diabetes. This represented 41.0% of patients with an hemoglobin A1c > 6.5% and 9.3% of all ICU patients. Compared with patients without diabetes, patients with unknown diabetes had a higher likelihood of requiring an insulin infusion (44.3% vs 29.3%; p < 0.0001), a higher average blood glucose (172 vs 126 mg/dL; p < 0.0001), an increased percentage of hyperglycemia (19.7% vs 7.0%; blood glucose > 180 mg/dL; p < 0.0001) and hypoglycemia (8.9% vs 2.5%; blood glucose < 70 mg/dL; p < 0.0001), higher glycemic variability (55.6 vs 28.8, average of patient sd of glucose; p < 0.0001), and increased mortality (13.8% vs 11.4%; p = 0.01). Conclusions: Patients with unknown diabetes represent a significant percentage of ICU admissions. Measurement of hemoglobin A1c at admission can prospectively identify a population that are not known to have diabetes but have significant challenges in glycemic control in the ICU.

Original languageEnglish
Pages (from-to)e541-e550
JournalCritical Care Medicine
Issue number12
StatePublished - 1 Dec 2015
Externally publishedYes


  • diabetes
  • glucose
  • hemoglobin A1c
  • insulin
  • intensive care unit


Dive into the research topics of 'Prevalence and impact of unknown diabetes in the ICU'. Together they form a unique fingerprint.

Cite this